Wednesday, July 9, 2014

Scientists Study Effects of Melting Glaciers in Prince William Sound

Federal and university scientists engaged in an ocean acidification study hope to learn by autumn how much impact glacial melt water is having on the saturation state of carbonate minerals in Alaska’s Prince William Sound.

“If the saturation state becomes too low, the waters can become corrosive to shell building organisms,” said Jeremy Mathis, an oceanographer at NOAA’s Pacific Marine Environmental Laboratory. 

Mathis, who is also an affiliate professor at the Institute of Marine Science, at the University of Alaska Fairbanks, said greater efforts are needed to slow the release of carbon dioxide into the atmosphere. The glacier melt itself has some unique chemistry that exacerbates ocean acidification, he said.

 “We need to understand how the water chemistry is changing in the sound,” Mathis said in an interview on July 8. “That will provide a foundation for understanding the impact of ocean acidification on the fisheries in Prince William Sound.”

Meanwhile scientists are thinking about what can be done in the way of mitigation efforts and strategies, so if they see a decline in fisheries they can respond, and have some adaptive capabilities in these fisheries resources.

 “The glacial melt water entering the sound has low concentrations of carbonate ion, which marine organisms need to build shells and skeletons,” Mathis said.  “When increasing amounts of this freshwater enter the sound, it makes surface water less hospitable for animals that build shells.”

To learn more, scientists from the Pacific Marine Environmental Laboratory, the University of Alaska and the Alaska Ocean Observing System earlier this spring launched two Carbon Wave Gliders and a Slocum underwater glider into the Gulf of Alaska to collect data for five months.

The Carbon Wave Gliders, which look and act like remotely-controlled surfboards, ride at the surface of the ocean, collecting data on water temperature, salinity, pH, dissolved oxygen and carbon dioxide in water and air.

The Slocum glider, which resembles a torpedo, and was conceived by Douglas C. Webb, tracks ocean data down to 200 meters.  It travels from a near shore ocean acidification buoy across the continental shelf and back. Scientists pilot the Slocum from the federal lab as well.  It provides data showing the downstream effects of melting glaciers and how freshwater changes the chemistry of the water column.  

This is the first time that these types of glides have been used in the cold waters of Alaska, NOAA officials said.

“Understanding these unique processes will help us determine which species are at risk, not just in Prince William Sound, but up and down the coast of the Gulf of Alaska,” Mathis said. “This information can help Alaskan communities better prepare for and adapt to ecosystem changes that may affect important fisheries.”

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